scholarly journals Wide-angle Reconfigurable Refraction by Silicon Fourier Metasurfaces

2021 ◽  
Vol 2015 (1) ◽  
pp. 012005
Author(s):  
A A Antonov ◽  
M V Gorkunov
Keyword(s):  
Analytical Approach ◽  
Numerical Solutions ◽  
Full Scale ◽  
Silicon Films ◽  
Angle Of Incidence ◽  
Wide Angle ◽  
Angular Range ◽  
Optical Setup ◽  
Fourier Harmonics ◽  
Rayleigh Hypothesis

Abstract We design metasurfaces based on silicon films with smooth relief described by several Fourier harmonics and study their ability to redirect the refracted light over a wide angular range controlled by subtle variations of the optical setup. We use semi-analytical approach based on the Rayleigh hypothesis as well as full-scale numerical solutions to optimize the relief shape. To illustrate the reconfigurability potential, we design metasurfaces efficiently redirecting the refracted light from 83° to −73° with respect to the normal, when the angle of incidence is varied from 0° to 2°, and from 80° to −74°, when the substrate permittivity is altered from 2.3 to 2.2.

Highly flexible wide angle of incidence terahertz metamaterial absorber: Design, fabrication, and characterization

2008 ◽  
Vol 78 (24) ◽  
Author(s):  
Hu Tao ◽  
C. M. Bingham ◽  
A. C. Strikwerda ◽  
D. Pilon ◽  
D. Shrekenhamer ◽  
...  
Keyword(s):  
Metamaterial Absorber ◽  
Angle Of Incidence ◽  
Wide Angle ◽  
Fabrication And Characterization

scholarly journals Analytical Approach to Polarization Mode Dispersion in Linearly Spun Fiber with Birefringence

2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
Vinod K. Mishra
Keyword(s):  
Analytical Approach ◽  
Numerical Solutions ◽  
Polarization Mode Dispersion ◽  
Optical Networking ◽  
Polarization Mode ◽  
Profile Function ◽  
Analytical Results ◽  
Mode Dispersion ◽  
Spun Fiber ◽  
Parameter Ranges

The behavior of Polarization Mode Dispersion (PMD) in spun optical fiber is a topic of great interest in optical networking. Earlier work in this area has focused more on approximate or numerical solutions. In this paper we present analytical results for PMD in spun fibers with triangular spin profile function. It is found that in some parameter ranges the analytical results differ from the approximations.

scholarly journals Eigenvalues and Eigenvectors for 3×3 Symmetric Matrices: An Analytical Approach

2020 ◽  
pp. 106-118
Author(s):  
Abu Bakar Siddique ◽  
Tariq A. Khraishi
Keyword(s):  
Analytical Solutions ◽  
Analytical Approach ◽  
Numerical Solutions ◽  
Linear Equations ◽  
Symmetric Matrices ◽  
Matrix Equations ◽  
Eigenvalues And Eigenvectors ◽  
Engineering Problems ◽  
The Matrix ◽  
Research Problems

Research problems are often modeled using sets of linear equations and presented as matrix equations. Eigenvalues and eigenvectors of those coupling matrices provide vital information about the dynamics/flow of the problems and so needs to be calculated accurately. Analytical solutions are advantageous over numerical solutions because numerical solutions are approximate in nature, whereas analytical solutions are exact. In many engineering problems, the dimension of the problem matrix is 3 and the matrix is symmetric. In this paper, the theory behind finding eigenvalues and eigenvectors for order 3×3 symmetric matrices is presented. This is followed by the development of analytical solutions for the eigenvalues and eigenvectors, depending on patterns of the sparsity of the matrix. The developed solutions are tested against some examples with numerical solutions.

scholarly journals 3D-Printed Low-Cost Dielectric-Resonator-Based Ultra-Broadband Microwave Absorber Using Carbon-Loaded Acrylonitrile Butadiene Styrene Polymer

Materials ◽  
2018 ◽  
Vol 11 (7) ◽  
pp. 1249 ◽  
Author(s):  
Jian Ren ◽  
Jia Yin
Keyword(s):  
Dielectric Resonator ◽  
Fused Deposition Modeling ◽  
Low Cost ◽  
Acrylonitrile Butadiene Styrene ◽  
Microwave Measurement ◽  
Angle Of Incidence ◽  
Wide Angle ◽  
Fused Deposition ◽  
Operating Band ◽  
Butadiene Styrene

In this study, an ultra-broadband dielectric-resonator-based absorber for microwave absorption is numerically and experimentally investigated. The designed absorber is made of the carbon-loaded Acrylonitrile Butadiene Styrene (ABS) polymer and fabricated using the 3D printing technology based on fused deposition modeling with a quite low cost. Profiting from the fundamental dielectric resonator (DR) mode, the higher order DR mode and the grating mode of the dielectric resonator, the absorber shows an absorptivity higher than 90% over the whole ultra-broad operating band from 3.9 to 12 GHz. The relative bandwidth can reach over 100% and cover the whole C-band (4–8 GHz) and X-band (8–12 GHz). Utilizing the numerical simulation, we have discussed the working principle of the absorber in detail. What is more, the absorption performance under different incident angles is also simulated, and the results indicate that the absorber exhibits a high absorptivity at a wide angle of incidence. The advantages of low cost, ultra-broad operating band and a wide-angle feature make the absorber promising in the areas of microwave measurement, stealth technology and energy harvesting.

scholarly journals PARTICLE SWARM OPTIMIZATION FOR OPTIMAL DESIGN OF BROADBAND MULTILAYER MICROWAVE ABSORBER FOR WIDE ANGLE OF INCIDENCE

2015 ◽  
Vol 62 ◽  
pp. 121-135 ◽  
Author(s):  
Subhanwit Roy ◽  
Souptik Dutta Roy ◽  
Jyotirmay Tewary ◽  
Ananya Mahanti ◽  
Gautam Kumar Mahanti
Keyword(s):  
Particle Swarm Optimization ◽  
Optimal Design ◽  
Particle Swarm ◽  
Microwave Absorber ◽  
Angle Of Incidence ◽  
Wide Angle ◽  
Swarm Optimization

Radiative Properties of Patterned Wafers With Nanoscale Linewidth

2006 ◽  
Vol 129 (1) ◽  
pp. 79-90 ◽  
Author(s):  
Y.-B. Chen ◽  
Z. M. Zhang ◽  
P. J. Timans
Keyword(s):  
Numerical Solutions ◽  
Radiative Properties ◽  
Wafer Surface ◽  
Angle Of Incidence ◽  
Patterned Wafers ◽  
Rigorous Coupled Wave Analysis ◽  
Recent Developments ◽  
Effects Of Temperature ◽  
Rigorous Coupled Wave ◽  
Feature Dimension

Abstract Temperature nonuniformity is a critical problem in rapid thermal processing (RTP) of wafers because it leads to uneven diffusion of implanted dopants and introduces thermal stress. One cause of the problem is nonuniform absorption of thermal radiation, especially in patterned wafers, where the optical properties vary across the wafer surface. Recent developments in RTP have led to the use of millisecond-duration heating cycle, which is too short for thermal diffusion to even out the temperature distribution. The feature size is already below 100nm and is smaller than the wavelength (200-1000nm) of the flash-lamp radiation. Little is known to the spectral distribution of the absorbed energy for different patterning structures. This paper presents a parametric study of the radiative properties of patterned wafers with the smallest feature dimension down to 30nm, considering the effects of temperature, wavelength, polarization, and angle of incidence. The rigorous coupled wave analysis is employed to obtain numerical solutions of the Maxwell equations and to assess the applicability of the method of homogenization based on effective medium formulations.

scholarly journals Scaling the Retinal Image of the Wide-Angle Eye Using the Nodal Point

Photonics ◽  
2021 ◽  
Vol 8 (7) ◽  
pp. 284
Author(s):  
Michael Simpson
Keyword(s):  
Linear Relationship ◽  
Retinal Image ◽  
Nodal Point ◽  
Axial Distance ◽  
Actual Behavior ◽  
Wide Angle ◽  
Angular Range ◽  
Exit Pupil

Angles subtended at the second nodal point of the eye (NP2) are approximately the same as input visual angles over a very large angular range, despite the nodal point being a paraxial lens property. Raytracing using an average pseudophakic eye showed that the angular nodal point criterion was only valid up to about 10°, and that the linear relationship was due instead to the cornea and lens initially creating chief ray angles at the exit pupil that are about 0.83 times input values for this particular eye, and then by the retina curving around to meet the rays in a manner that compensates for increasing angle. This linear relationship is then also maintained when retinal intersections are calculated relative to other axial points, with angles rescaled approximately using the equation R/(R + delta), where delta is the axial distance from the center of a spherical retina of radius R. Angles at NP2 approximately match the input angles, but the terminology is misleading because this is not a paraxial property of the eye. Chief rays are used with finite raytracing to determine the actual behavior.

Analytical approach calculating eigenfrequencies and modes of stator cores in AC machines

2012 ◽  
Vol 61 (1) ◽  
pp. 47-56 ◽  
Author(s):  
Paweł Witczak
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Differential Equations ◽  
Dynamic Analysis ◽  
Analytical Approach ◽  
Numerical Solutions ◽  
Two Dimensional ◽  
Ac Machines ◽  
Magnetic Forces ◽  
Element Method

Analytical approach calculating eigenfrequencies and modes of stator cores in AC machinesThe paper describes analytical approach solving the problem of dynamic analysis of two-dimensional fields of vibrational displacements and rotations caused by magnetic forces acting on stator of AC machine. Final set of three differential equations converted into algebraic ones is given and it is confronted with numerical solutions obtained by finite element method.

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